To develop strategies to facilitate the application of magnetic resonance imaging (MRI) to the detection of malignant growths. Specifically to develop contrast agents to enhance the vizualization of tumors. These agents are considered to be valuable both for the increase in intrinsic contrast relative to surrounding soft tissue, as well as the discrimination between benign and malignant growths by MRI. Also, by the use of MRI to attempt to localize the in vitro distribution of anti-cancer drugs.